Wiper device, especially for windshields of automobiles

ABSTRACT

A wiper system has a driveable wiper arm ( 20 ) guided at one end on the motor vehicle. A long-straggling wiper blade ( 12 ) capable of being placed against the window ( 16 ) with a wiper strip ( 22 ) is detachably hinge-mounted via a connection device ( 18 ) that has a pivot bolt ( 24 ) on the arm side. The axis of articulation of the pivot bolt extends substantially transversely to the longitudinal direction of the wiper blade in the working direction of the wiper system. The system includes a coupling part ( 26 ) on the wiper-blade side in a center section of the wiper blade ( 12 ) on its side opposite from the window ( 16 ) having a bore-like bearing receptacle for a pivot bolt ( 24 ). The bearing receptacle is provided with a bottleneck ( 94 ) capable of being expanded elastically to the diameter ( 92 ) of the pivot bolt.

BACKGROUND OF THE INVENTION

A wiper system according to the invention comprises the driven wiper armas well as the wiper blade to be fastened on its one exposed end. Theconnection device required for this has appropriately developed couplingmeans corresponding with each other on the arm side and the blade side.

In the case of a known wiper system (DE 23 13689 A1), the wiper bladebelonging to the wiper system and its coupling pan has a guide channelopen toward a main body of the wiper strip, in which a hair pin-shapedretaining spring is displaceable between an installation position and alocked position. This retaining spring serves to open or close a recesslocated in the coupling part that represents the bearing receptacle forthe wiper arm-pivot bolt. The retaining spring is preloaded toward arubber main body of the wiper strip so that the friction between therubber and the spring must be overcome in order to displace the spring.On the one hand, the ability of the spring to be displaced must be easyto manage for the user, e.g., when replacing the wiper blade, and, onthe other hand, the spring must reliably close the bearing receptacle inthe channel wall during the wiping operation so that the wiper bladecannot detach unintentionally from the wiper arm. These two opposingrequirements cannot be fulfilled equally to satisfaction.

In the case of another wiper system (DE-PS 10 28 896) that does not havethis deficiency, a coupling part on the wiper blade side is integrallymolded to the rubber-elastic wiper strip. The coupling part has abore-type bearing receptacle for a pivot bolt on the arm side that canbe inserted in the bearing receptacle of the wiper blade transversely toits longitudinal axis via an elastically-expandable installation slot.This type of articulation may function reliably at best at low drivingspeeds and in the presence of small amounts of precipitation in the formof rain. When precipitation is strong and/or driving speeds are high, orprecipitation is present in the form of snow, particularly in the formof wet snow, the forces exerted by the wiper blade on the articulationcan exceed the holding power of the rubber-elastic coupling part anddetach the wiper blade from the wiper arm.

SUMMARY OF THE INVENTION

The wiper system according to the invention is unique by virtue of asimple end functionally-secure articulation between the wiper arm andwiper blade. The attach the wiper blade to the wiper arm, its pivot boltis inserted into the bearing receptacle of the wiper blade while thebottleneck is temporarily elastically expanded, whereby the lockingelement is moved into its open position against the return force, sothat the pivot bolt reaches it bearing receptacle. The return force thenautomatically moves the locking element into Its locked position. Thelocking element can be produced out of a material that is so stiff thatthe operating forces acting on the point of articulation are absorbedbetween the wiper blade and the wiper arm without any negativeconsequences for the articulation.

A simple design of the wiper system results from the fact that thecoupling part has a housing part that is permanently interconnected withthe wiper blade, on which said housing part the locking element isdisplaceably guided in the longitudinal direction of the wiper blade.

In order to obtain a particularly robust design of the coupling forattaching the wiper blade to the wiper arm, the housing part has twoguide walls that extend in the longitudinal direction of the wiper bladeand are located at a distance from each other, between which the lockingelement is displaceably guided.

When, in a further embodiment of the invention, the bearing receptaclefor the pivot bolt of the wiper arm penetrates the two guide walls aswell as the locking element, whereby the recesses in the guide wallsadapted to the cross section of the pivot bolt and the locking elementlocated in the locked position complement each other to at leastapproximately form a circle, as viewed in the direction of the axis ofarticulation, the result is a functionally-secure, free-from-play fixinginto position of the wiper arm-side pivot bolt in the coupling part ofthe wiper blade, therefore resulting as well in a smooth motion of thewiper blade over the window to be wiped. So that the wiper blade canalso be attached to the wiper arm by individuals not skilled in the art,each of the bearing receptacle sections developed in this fashion isopen toward the side of the coupling part opposite from the window overone section of the pass-through channel each, whereby the width of eachpass-through channel section is greater than the diameter of the pivotbolt.

The locking element is preferably loaded toward the locked position byspring means supported on the housing part. This can be obtained incost-effective fashion by means of a helical compression spring formingthe spring means.

Installation of the coupling part can be simplified by the fact that thespring means are formed by a leg spring interconnected as a singlecomponent with the housing part composed of an elastic plastic.

When the bearing section of the locking element is provided with astarting incline that is opposite from its recess at a distance and thatforms an acute angle α with the direction of displacement of the lockingelement, the detachment of the wiper blade from the wiper arm can beachieved in simple fashion by moving the locking element into its openposition, whereby the starting incline presses the pivot bolt out of thebearing sections into the guide walls.

A permanently stable guidance of the locking element between the twoguide walls is obtained when the two guide walls are interconnected by abridge at one end section of the housing part.

In order to prevent mistakes during installation of the locking elementin the housing part, the housing part has means for ensuring a definedworking motion for the locking element located at a distance from thewiper strip.

These means can be formed in cost-effective fashion by means of at leastone strip-like projection on the inside of one guide wall that extendsin the direction of the working motion of the locking element and withwhich a longitudinal groove matched to the cross section of theprojection and located on the side wall of the locking element facingthe projection is associated.

To secure the locking element in the housing part, a limiting shoulderpointing in the direction opposite from the working direction issituated on said housing part, which said limiting shoulder cooperateswith a counter-shoulder located on the locking element.

A further means for obtaining a free-from-play guidance of the wiperblade on the wiper arm can be obtained by the fact that the wiper armhas two side walls situated at a distance from each other and parallelto each other at least in the region of the pivot bolt, which said sidewalls are arranged standing upright on the window, and on which the endsof the wiper arm are fastened, whereby the distance between the two sidewalls is matched to the width of the coupling part. The two side wallstherefore overlap the outer sides of the two guide walls opposite fromeach other in a manner that is free from play and covers a large area.

A particularly low and easy-to-build wiper blade is obtained when thecoupling part is held on the top surface—opposite from the window—of aband-like long-straggling, spring-elastic carrier element, whereby itlies flat on said carrier element over at least one subsection, andwhen, furthermore, a rubber-elastic wiper strip capable of being placedagainst the window and arranged parallel to the longitudinal axis islocated on the bottom band surface of the carrier element facing thewindow.

Further advantageous further developments and embodiments of theinvention are presented in the subsequent description of exemplaryembodiments illustrated in the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of the schematic illustration of a wiper systemaccording to the invention.

FIG. 2 shows the enlarged perspective illustration of a detail labelled“II” in FIG. 1, whereby the wiper blade is detached from the wiper arm.

FIG. 3 shows a cross section through the wiper blade along the lineIII—III in FIG. 2.

FIG. 4 shows a partial longitudinal sectional drawing through the wiperblade located in the attached position along the line IV—IV in FIG. 2.

FIG. 5 shows the arrangement according to FIG. 4 drawn in the detachingposition.

FIG. 6 shows another embodiment of the arrangement according to FIG. 4.

FIG. 7 shows the arrangement according to FIG. 6 in the detachingposition.

FIG. 8 shows an enlarged partial illustration of the arrangementsaccording to FIGS. 4 and 6 in an intermediate detaching position.

FIG. 9 shows a sectional drawing along the line IX—IX in FIG. 4.

FIG. 10 shows the arrangement according to FIG. 9 in the positionaccording to FIG. 5.

FIG. 11 shows a side view of a locking slide belonging to the wipersystem.

FIG. 12 shows a top view of the locking slide according to FIG. 11,partially cut.

FIG. 13 is a side view of a coupling part belonging to a wiper systemalong the line XIII—XIII in FIG. 14, partially cut.

FIG. 13 shows a top view of the coupling part according to FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A wiper system 10 shown in FIGS. 1 and 2 has a wiper blade 12 with aband-like long-straggling, spring-elastic carrier element 14. Aconnection device 18 lying flat on the carrier element is located on thetop surface of the band 13 of the carrier element opposite from thewindow 16 to be wiped, with the aid of which said connection device thewiper blade 12 can be detachably interconnected with a driveable wiperarm 20 belonging to the wiper system and guided at one end on the bodyof a motor vehicle. A long-straggling, rubber-elastic wiper strip 22 issituated parallel to the longitudinal axis on the bottom band surface 15of the carrier element 14 facing the window 16. A pivot bolt 24 servingas a coupling means on the arm side is held on the exposed end 21 of thewiper arm 20, which said pivot bolt is supported in a bearing receptacleof a coupling part 26 on the wiper blade side. The exposed end of thewiper arm 20 is loaded in the direction of the arrow 30 toward thewindow 16 to be wiped, the surface to be wiped of which is representedin FIG. 1 by a dash-dotted line 28. Since the dash-dotted line 28 isintended to represent the greatest curvature of the window surface, itis obvious that the curvature of the wiper blade 12 lying against thewindow with its two ends is greater than the maximum curvature of thewindow. Under the contact pressure (arrow 30), the wiper blade bearsagainst the window surface 28 with its wiper lip 32 along its entirelength. A tension therefore builds up in the band-like, spring-elasticcarrier element 14 that ensures that the wiper strip 22 or the wiper lip32 is seated properly against the motor vehicle window 16 along itsentire length. Due to the use of the carrier element 14, a wiper bladecarrier strap system (DE-PS 15 05 397) known for a long time is renderedsuperfluous.

The special embodiment of the wiper system 10 according to the inventionshall now be discussed in greater detail hereinbelow. The wiperblade-side coupling part 26 of the connection device 18 is designed as adouble component. It has a housing part 34 (FIGS. 13 and 14) with twoparallel guide walls 36 and 38 situated at a distance from each otherand extending in the longitudinal direction of the wiper blade 12, whichsaid guide walls are interconnected at its one end section by means of abridge-like member 40 ensuring the stability of the housing part. Thetwo inner sides of the guide walls 36, 38 facing each other form guidesurfaces for a slide-like locking element 42 (FIGS. 11 and 12) that alsobelongs to the coupling part 26. To ensure a defined working motion forthe locking slide 42, a strip-like projection 44 extending in thelongitudinal direction of the wiper blade is located on each of theinner sides of the guide walls 36, 38 facing each other. To ensure adefined working motion, longitudinal grooves 46 located on the lockingslide 42 and matched to the cross section of the projections 44 areassociated with the strip-like projections 44. The slide-like lockingelement 42 can therefore be slid, without play, between the guide walls36 and 38 in the longitudinal direction of the wiper blade. To securethe locking slide 42 in the housing part 34, a limiting shoulder 48pointing in the direction opposite from the working motion is located oneach of the two projections 44. The two limiting shoulders 48 cooperatewith counter-shoulders located on the locking slide in its longitudinalgrooves in the sense of limiting the working motion. On the end sectionof the housing part 34 provided with the bridge 40, said end section isprovided with an end wall 52, the inner side 54 of which faces thelimiting shoulders 48 at a distance. A helical coiled spring 56 issupported on the inner side 54 in preloaded fashion (FIGS. 4 and 9),which said helical coiled spring pushes the locking slide 42 built intothe housing part 34 in the direction of the arrow 58 (FIG. 9), wherebythe limiting shoulders 48 catch the locking slide 42 at itscounter-shoulders 50 when it has reached its locked position. Thehelical coiled spring 56 is thereby still under a slight preload. In anoperating position of the connection device 18 shown in FIG. 4, thelimiting shoulders 48 are situated at a slight distance away from thecounter-shoulders 50. This means that the locking slide 42 serving as alocking element is moved slightly in the direction of the arrow 60 (FIG.4) against the working direction of the helical coiled spring 56. Inthis operating position, the coupling part 26 is penetrated by abore-like bearing receptacle for the pivot bolt 24 transversely to thedirection of motion of the locking slide 42. The bearing receptacle 62therefore penetrates both guide walls 36, 38 and the locking slide 42.To facilitate a better understanding, the pivot bolt 24 has been drawnin cross section in FIG. 4. The recesses in the guide walls 36, 38resulting thereby are complemented by the recess 66 resulting in thelocking slide 42 in its locked position and approximately form a circlethat is matched to the cross section of the pivot bolt. So that thelocking slide can be moved in the direction of the arrow 60 from itsoperating position shown in FIG. 4 into an open position (FIG. 5), it isprovided with a recess 68 on the side opposite from its recess 66. Therecess is selected so large in size that it forms a pass-through channelsection for the pivot bolt. The recesses 64 in the guide walls 36, 38are also opened in the manner of a funnel via pass-through channelsections 70 (FIG. 13). The width of the pass-through channel sections isselected so that the pivot bolt 24 can be inserted easily into thewall-side recesses 64 in the direction of the arrow 72 (FIG. 13). As aresult of the recess 68 in the locking slide 42 that is dimensionedaccordingly, the pivot bolt 24 can also easily reach the bearing recess66 in the locking slide 42 (FIG. 11). This is only possible, however,when the locking slide 42 is moved into its open position shown in FIG.5 in the direction of the arrow 60 (FIG. 5) against the clamping forceof the helical coiled spring 56. In this open position, a pass-throughchannel 71 for the pivot bolt results, which said pivot bolt extendsover the entire width of the housing part, including the locking slide42 guided in said housing part. The bearing receptacle sections formedin this fashion and arranged in tandem in the direction of the axis ofthe pivot bolt 24—which said bearing receptacle sections are formed bythe recesses 64 and 66 in the housing part 26 and by the recess 68, 69in the locking slide 42—bare therefore open toward the side of thecoupling part 26 opposite from the window. The width of each section isthereby greater than the diameter of the pivot bolt. The recess 66 inthe locking slide 42 is provided with a starting incline 74 that isopposite from the recess 66 at a distance and that forms an acute angleα with the direction of displacement of the locking element (FIG. 8).

It is obvious in FIGS. 2 and 3 that the wiper blade-side coupling part26 of the connection device 18 is interconnected with the carrierelement 14 sitting on the top band surface 13 of the carrier element 14.In the region of the line of cut III—III, the carrier element 14 has twospring strips 80 gripping the wiper strip and located at a distance fromeach other and parallel to each other, the inside edges of which reachinto the longitudinal grooves of the wiper strip 22, and the outer edgesof which are gripped by longitudinal grooves 82 present in the guidewalls 36 and 38. The arrangement of the wiper strip 22 is therebyaffected such that it does not bear against the locking slide 42 andinfluence its working motion. As illustrated in FIG. 2, the wiper arm 20has a U-shaped cross section on its exposed end 21. It therefore has twoside walls situated at a distance from each other and parallel to eachother, which said side walls are situated standing upright toward thewindow. The two ends of the pivot bolt 24 are fixed at the side walls84. The distance 83 between the inner sides of the side walls 84 facingeach other is matched to the width 85 of the housing part 34 in such afashion that the side walls 84 overlap the outer sides of the guidewalls 36, 38 in a manner that is free from play. Excellent lateralstability for the wiper blade on the wiper arm therefore results whenthe wiper system 10 is moved in the direction of the double arrow 88(FIG. 2) over the window to be wiped.

An alternative to the arrangement of a helical coiled spring illustratedpreviously is shown in FIGS. 6 and 7. Since this other exemplaryembodiment differs from the exemplary embodiment described withreference to FIGS. 4 and 5 only in terms of the design of the springmeans, the reference numerals used previously for the locking slide willbe used again here. The coupling part 126 according to FIGS. 6 and 7also has a housing part 134 and a locking slide 42 with thecorresponding bearing receptacles 62, pass-through channels 71 andrecesses. The locking slide 42 also has a recess 68 with the startingincline 74. The housing part 134 is produced out of an elastic plastic,however. A leg spring 156 is integrally molded to the bridge connectingthe two guide walls 36 and 38, which said leg spring performs thefunction of the helical coiled spring 56 in the exemplary embodimentaccording to FIGS. 4 and 5. The leg spring 156 is adjusted so that itstill bears against the locking slide 42 with preload in the operatingposition (locked position) shown in FIG. 6. When the locking slide 42 ismoved in the direction of the arrow 60 and is brought into its openposition shown in FIG. 7, the leg spring 56 deflects with increasingtension, so that the locking slide 42 exposes the pass-through channelsections.

In addition to further described features, the wiper system 10 accordingto the invention also has a bore-like bearing receptacle 62 for thepivot bolt 24, whereby the bearing receptacle is open-edged along itscylindrical surface over a pass-through channel 71 pointing in thedirection of the bore axis. The pass-through channel is divided intothree different sections, whereby one section 70 each is located in theguide walls 36, 38, and a third section 68, 69 is located in the lockingslide 42. The pass-through channel sections in the two guide walls 36and 38 has a width 90 in the region of the bearing receptacle 62 (FIG.8) that is somewhat greater than the diameter 92 of the pivot bolt 24.

When the loose wiper blade 12 is to be attached to the wiper arm 20, itis moved into the position shown in FIG. 2. The wiper blade is thenmoved upward toward the pivot bolt 24, whereby the funnel-shaped recess64 in the guide walls 36, 38—together with the side walls 84 of thewiper arm end 21 sliding along the outer sides of the guide walls in thedirection of the arrow 72 (FIG. 8)—act as a very good installation aid.In this installation motion, the locking slide 42 is displaced by thepivot bolt 23 in the direction of the arrow 60—while the tension of thespring means 56 and 156 increases—until the pivot bolt 24 reaches itsbearing receptacle 62 formed by the recesses 64 and 66 (open position).The locking slide then snaps into its operating position shown in FIG. 4under the effect of the spring means 56 and 156, which is nowsubstantially preloaded. The locking slide 42, with the upper edge 67 ofits recess 66, now constricts the pass-through channel to a bottleneck94 (FIG. 4), the width of which is less than the diameter of the pivotbolt 23, so that the wiper blade 12 can no longer be detached from thewiper arm 20 (locked position). The pivot bolt is then practicallyenclosed by parts of the coupling part 24.

To detach the wiper blade 12 from the wiper arm 20, the locking slide 42must be moved in the direction of the arrow 60 while the bottleneck 94expands elastically, whereby the starting incline 74 of the lockingslide 42 impacts the pivot bolt 24 and lifts it out of its bearingreceptacle 62, as illustrated in FIG. 8. As FIG. 8 further shows, inthis position, the bottleneck 94 is already expanded so far that itswidth 90 is already greater than the diameter 92 of the pivot bolt 24(open position). Accordingly, the wiper blade can be immediatelydetached from the pivot bolt, and, therefore, from the wiper arm, in thedirection opposite from the direction of the arrow 72. The wiper systemis therefore unique in that the coupling part 26 is provided with aseparate locking element 42 to form the bottleneck 94, which saidlocking element is capable of being moved, against the return force(arrow 96), out of its locked position—which corresponds to theoperating position—that blocks the pass-through channel into an openposition that exposes the pass-through channel (FIGS. 5 and 8).

What is claimed is:
 1. A wiper system, in particular for motor vehiclewindows, comprising a driveable wiper arm, (20) guided at one end on themotor vehicle, wherein, on an exposed end (21) of said wiper arm, awiper blade (12) capable of being placed against the window (16) with awiper strip (22) is detachably hinge-mounted via a connection device(18), wherein said connection device has a pivot bolt (24) on an armside, wherein an axis of articulation of said pivot bolt extendssubstantially transversely to a longitudinal direction of the wiperblade in a working direction of the wiper system (10), and which has acoupling part (28) with a bore-type bearing receptacle (62) for thepivot bolt (24) on a wiper blade side in the center section of the wiperblade on a side opposite from the window, whereby the bearing receptacle(62) is open-edged along a cylindrical surface over a pass-throughchannel (70) for the pivot bolt pointing in the direction of the boreaxis, wherein said bearing receptacle is provided with a bottleneck (94)capable of being expanded elastically to a diameter (92) of the pivotbolt, wherein the width of said bottleneck is smaller than the diameterof the bearing receptacle, wherein the coupling part (26) is providedwith a separate locking element (42) to form the bottleneck, whereinsaid locking element is capable of being moved, against a return force(96), from a locked position that blocks the pass-through channel intoan open position that exposes the pass-through channel, wherein thebearing receptacle (62) for the pivot bolt (24) of the wiper arm (20)penetrates two guide walls (36, 38) and the locking element (42),whereby recesses (64, 66) adapted to a cross section of the pivot boltin the guide walls and in the locking element located in the lockedposition complement each other to at least approximately form a circleas viewed in the direction of the axis of articulation, wherein each ofthe bearing receptacle sections is open over one pass-through channelsection toward a side of the coupling part (26) opposite from thewindow, whereby the width of each section is greater than the diameterof the pivot bolt (24), wherein the locking element (42) is loadedtoward the locked position by spring means supported at the housing part(34), and wherein the spring means are formed by a leg spring (156)interconnected as a single component with the housing part (134)composed of an elastic plastic.
 2. The wiper system according to claim1, wherein the coupling part (26) has a housing part (34) permanentlyinterconnected with the wiper blade (12), wherein on said housing part,the locking element (42) is displaceably guided in the longitudinaldirection of the wiper blade (12).
 3. The wiper system according toclaim 2, wherein the housing part (34) has two guide walls (36, 38)extending in the longitudinal direction of the wiper blade located at adistance from each other, wherein the looking element (42) isdisplaceably guided between said two guide walls.
 4. The wiper systemaccording to claim 3, wherein the two guide walls (36, 38) areinterconnected at an end section of the housing part (34) by means of abridge (40).
 5. The wiper system according to claim 2, wherein thehousing part (34) is provided with means (44) for ensuring a definedworking motion for the locking element (42) located at a distance fromthe wiper strip (22).
 6. The wiper system according to claim 5, whereina limiting shoulder (48) is located on the housing part (26) oriented ina direction against the working motion that cooperates with acounter-shoulder (50) located on the locking element (42).
 7. The wipersystem according to claim 1, wherein the bearing section of the lockingelement (66) is provided with a starting incline (74) that faces therecess (66) in said bearing section at a distance and which forms anacute angle (Δ) with a direction of displacement (60) of the lockingelement.
 8. The wiper system according to claim 1, wherein the wiper arm(20), at least in the region of the pivot bolt (24), has two side wails(84) located at a distance from each other and parallel to each otherthat are situated standing upright to the window (16) and to which theends of the pivot bolt (24) are secured, and the distance (83) betweenthe two side walls is matched to the width (86) of the coupling part(26).
 9. The wiper system according to claim 1, wherein the couplingpart (34) is held on a top band surface of a spring-elastic carrierelement opposite from the window (16), whereby the coupling part liesflat on said carrier element at least over one subsection, and arubber-elastic wiper strip (22) capable of being placed against thewindow is located parallel to the longitudinal axis on another bottomband surface (15) of the carrier element (14) facing the window.
 10. Awiper system, in particular for motor vehicle windows, comprising adriveable wiper arm (20) guided at one end on the motor vehicle,wherein, on an exposed end (21) of said wiper arm, a wiper blade (12)capable of being placed against the window (16) with a wiper strip (22)is detachably hinge-mounted via a connection device (18), wherein saidconnection device has a pivot bolt (24) on an arm side, wherein an axisof articulation of said pivot bolt extends substantially transversely toa longitudinal direction of the wiper blade in a working direction ofthe wiper system (10), and which has a coupling part (26) with abore-type bearing receptacle (62) for the pivot bolt (24) on a wiperblade side in the center section of the wiper blade on a side oppositefrom the window, whereby the bearing receptacle (62) is open-edged alonga cylindrical surface over a pass-through channel (70) for the pivotbolt pointing in the direction of the bore axis, wherein said bearingreceptacle as provided with a bottleneck (94) capable of being expandedelastically to a diameter (92) of the pivot bolt, wherein the width ofsaid bottleneck is smaller than the diameter of the bearing receptacle,wherein the coupling part (26) is provided with a separate lockingelement (42) to form the bottleneck, wherein said locking element iscapable of being moved, against a return force (96), from a lookedposition that blocks the pass-through channel into an open position thatexposes the pass-through channel, wherein the coupling part (26) has ahousing part (34) permanently interconnected with the wiper blade (12),wherein on said housing part, the locking element (42) is displaceablyguided in the longitudinal direction of the wiper blade (12), whereinthe housing part (34) is provided with means (44) for securing a definedworking motion for the locking element (42) located at a distance fromthe wiper strip (22), wherein said securing means are formed by at leastone strip-like projection (44) on an inside of one guide wall (36, 38)that extends in the direction of the working motion of the lockingelement (42), and wherein a longitudinal groove (46) matched to a arosesection of the projection on a side wall of the locking element (42)facing the projection is associated with the projection.
 11. The wipersystem according to claim 10, wherein the spring means are formed by ahelical compression spring (56).